An out‑of‑bounds write in the Windows Fast FAT Driver can be triggered by an authorized attacker, allowing that user to gain elevated local privileges. This memory corruption flaw is a classic buffer overflow (CWE‑787) that can corrupt user‑mode memory and undermine system integrity.

The flaw affects multiple Microsoft Windows releases, including Windows 10 versions 1607, 1809, 21H2, and 22H2; Windows 11 versions 23H2, 24H2, 25H2, 26H2, and 26H1; and Windows Server editions 2012, 2012 R2, 2016, 2019, 2022, and 2025. All listed builds that deploy the Windows Fast FAT Driver are potentially vulnerable.

The CVSS score of 7.0 indicates a medium‑to‑high impact if successful. Because the vulnerability requires local access, the EPSS score is not available, and it is not yet listed in the CISA KEV catalogue, exploitation is likely limited to environments where an attacker can execute code with sufficient privilege. The attack vector is inferred to be local, and administrators should treat the flaw as a significant potential privilege‑escalation risk until a patch is applied.